Method of raising beef cattle and sheep and feed rations for use therein



United States Patent Oflice 2,751,303 Patented June 19, 1956 METHOD OFRAISING BEEF CA'ITLE AND SHEEP AND FEED RATIONS FOR USE THEREIN WiseBurroughs, Antes, Iowa, alslpor to Iowa State College ResearchFoundation, Inc., Ames, Iowa, n corporation of Iowa No Drawing.Application November 9, 1955, Serial No. 546,008

Claims. cl. 9s 2 This invention relates to a method of raising beefcattle and sheep and to feed rations for use therein. The method andfeed materials of this invention have particular utility in growing andfattening beef cattle for the purpose of producing high-quality beef atan accelerated rate with a reduced amount of feed.

This application is a continuation-in-part of my copending applicationSerial No. 440,268, filed June 29, 1954, which in turn was acontinuation-in-part of my application Serial No. 359,449, filed June 3,1953, and now abandoned.

The present invention is concerned with the oral administration ofestrogenic substances to growing beef cattle and sheep. To my knowledgeno one heretofore has even tested oral administration of estrogens togrowing beef cattle and sheep. The previous lack of interest in testingoral administration of estrogens in growing beef cattle and sheep haslikely stemmed from discouraging results obtained with oraladministration of estrogens to full grown dairy cattle. Dairy cattlerequire such large amounts of estrogens in their feed to bring about adesirable physiological response (e. g. increased milk production) thatthe practice has never been commercially feasible. It was thereforeunexpected to find that the physiology of lactation and/ or mammarygrowth in dairy cattle is sufiiciently different from the physiologyinvolving general growth and fattening in beef cattle and sheep thatmuch lower feeding levels of estrogens are required in the case of beefcattle thereby resulting in a highly profitable feeding procedure. Thisfinding was also unexpected because of the discouraging resultspreviously obtained with the oral administration of estrogens to poultryand hogs.

Due to the high levels of estrogens required when given orally topoultry, swine, and dairy cattle resort has been had to the method ofimplanting estrogenic substances subcutaneously in the form of pellets.This method of administration when tried with growing beef cattle andlambs has not been satisfactory. While in some cases the rate of weightgain has appeared to be accelerated, in nearly all cases the meatproduced is of inferior quality than when estrogenic substances are notgiven.

It has also been thought that the administration of estrogenicsubstances to growing beef cattle and sheep including castrated malecattle (steers) and both male and female lambs, suffers from a number ofinherent disadvantages, chief among which is excessive sexualstimulation of animals including mammary development and lactation aswell as other undesirable physiological side effects on the reproductivesystem. Further, when the estrogenic substances are given bysubcutaneous implantation of pellets into fattening animals there isdanger of residues from the pellets remaining in the meat afterslaughter, which may adversely affect the health of people consumingsuch meat.

The problem of providing growth stimulants for meatproducing animals isparticularly acute in connection with beef cattle and sheep since theseanimals have not proven particularly responsive to other growthstimulants such as antibiotics, vitamin B12, surfactants, etc.Therefore, there has been a long felt need for growth stimulantcompositions which are effective with beef cattle and sheep whileovercoming the problems connected with the use of estrogenic substancesdiscussed above, and for a practical commercial method of employing suchcompositions.

lt is therefore a general object of this invention to provide a methodof treating growing beef cattle and sheep to promote growth or the rateof weight gain without causing undesirable physiological side effects,and at the same time producing at least as good or superior quality meatto that produced in the absence of the treatment. Further objects andadvantages will appear as the speci fication proceeds.

This invention is based in part on the discovery that estrogenicsubstances when orally administered to growing beef cattle and sheepsubstantially accomplish the objects of this invention and provide asolution to the problems discussed above. More specifically, it has beenfound that the oral administration of estrogenic substances to beefcattle and sheep is capable of producing a pronounced acceleration inthe rate of weight gain in the animals without causing untoward sideefiects and at the same time producing better quality meat. In one ofits phases, this invention is concerned with a method of treatinggrowing beef cattle and sheep characterized by the steps of orallyadministering an estrogenic substance at spaced intervals of time over asubstantial portion of the growth period of the animal, and regulatingthe quantities of the estrogenic substance thus administered to increasethe rate of weight gain without causing undesirable physiological sideeffects. Within this range, the feed eiliciency is substantiallyimproved while at the same time down grading of the carcasses isavoided.

An estrogenic substance is defined for the purpose of this invention asany chemical substance which, when properly administered in sufficientamounts, initiates estrus in sexually mature normal female animals.Estrogenic substances can be obtained from natural sources such asanimals and plants, but the commercially available estrogens areprincipally synthetic chemicals. Both synthetic and natural estrogenshave been tested and found to be operative for the purpose of thisinvention, but in general synthetic estrogens are preferred.Specifically, excellent results have been obtained with stilbestrolwhich is a synthetic derivative of stilbene and is sometimes alsoreferred to as diethylstilbestrol. Other natural and synthetic estrogenscan be used such as estradiol, derivatives of diethylstilbestrol,estrone, dianisylhexene, genistin, genistein, dienstrol, hexestrol, andthe like. A preferred subclass of estrogens can be described as thosehaving molecular structures similar to stilbestrol in containing twophenyl groups having free hydroxyl substituents.

While the estrogenic substance can be administered orally in other ways,it is preferred to first combine the very small quantity of thesubstance required with an animal feed or feed supplement which isadapted for use in feeding the particular animal, such as a cattle orsheep feed supplement. The usual practice in growing and fattening beefcattle, for example, is to feed a prepared supplement which, typically,may be about 10% by weight of the food consumed by the animals per day.These prepared feed supplements therefore provide a convenient vehiclefor the administration of the estrogenic substances in accordance withthis invention. However, it will be understood that if desired theestrogenic substance can be incorporated in the whole ration for theanimal or in other nutrient material which is consumed by the animal.

It has been found that the quantity of the estrogenic substance which isorally administered must be regulated to increase the rate of weightgain without causing undesirable physiological side effects. In otherwords, it is necessary to administer enough of the estrogenic substanceto produce a marked increase in the rate of weight gain but not so muchas to cause undesirable physiological side efiects as manifestedparticularly by visibly excessive sexual stimulation, or otherobservable effect on the reproductive system. More particularly, thephysiological side elfects which should be avoided in practicing thisinvention are indicated by undue restlessness, riding, high tail heads,marked udder development, mammary and lactation stimulation, sunkenloins, rectal or vaginal prolapse, and other comparable effects on thereproductive systems of the animals.

As indicated above, the quantity of estrogenic substance administered togrowing beef cattle and sheep must be controlled to produce the desiredincrease in the rate of weight gain as the animal matures withoutundesirable side eflects, and the present invention is based in part onthe discovery that this result can be achieved by controlling the amountof estrogenic substance administered to the animal. The necessary degreeof control can be achieved by administering the estrogenic substance inproportion to the body weight of the animal or in proportion to the feedintake of the animal. In fact, both of these methods of control canproduce equivalent results, since the number of pounds of food consumeddaily by growing sheep and beef cattle is roughly proportional to theweight of the animal. For example, when growing beef cattle are fullfed, they will usually consume about 3% of their weight per day in foodmaterial. Further, if the estrogenic substance is administered in a feedsupplement which forms only part of the total ration of the animal, theamount in the supplement can be proportionaly increased in inverserelation to the proportion of the feed supplement to the total feedintake.

When stilbestrol (diethylstilbestrol) is used in practicing the presentinvention, from 0.1 to 8 milligrams (mgm.) should be administered to thegrowing beef animal per 100 lbs. of body weight during each 24-hourperiod of treatment, or at least the average dosage per day should fallwithin this range over each to 10-day period of treatment. Preferably,from 0.1 to 3 mgm. of stilbestrol are administered per 100 lbs. of bodyweight over each 24-hour period. On the basis of feed intake, whenstilbestrol is incorporated in the total feed ration, the cattle feedmaterial should contain from .03 to 2.7 mgm. per pound of feed materialor, preferably, from .03 to 1.0 mgm. per pound of feed material.

The range within which beneficial results can be ob tained without alsoobtaining undesirable side eflects tends to be somewhat lower for sheepthan for cattle. Levels ranging from .01 to 5.0 mgm. of stilbestrol per100 lbs. of body weight per 24 hours can be used for sheep, while thepreferred range is the same as for beef cattle; e. g. 0.1 to 3.0 mgm. ofstilbestrol per 100 lbs. of body weight per 24 hours. Similarly, whenstilbestrol is incorporated in the total feed ration for the sheep, thesheep feed material can contain from .003 to 2.0 mgm. per pound of feedmaterial and preferably contains from .03 to 1.0 mgm. per pound of feedmaterial.

The importance of orally administering the estrogens in these specifiedamounts is further illustrated by the unexpected finding that estrogenswhen fed to beef cattle and lambs in the ranges indicated remainprimarily localized in the digestive tract and liver of treated animalswith only relatively minute amounts traversing the general bodycirculation. This finding is of considerable significance since itexplains why no undesirable side effects develop in the animals whenpracticing the invention since at the levels indicated essentially noneof the estrogen reaches the sex organs or rudimentary mammary glands. Bycontrast it explains why much larger amounts of orally administeredestrogens are required in dairy cattle in order to be physiologicallyeffective for stimulating lactation and mammary gland development. Sincelarger feeding amounts result in more estrogen traversing the generalcirculation to the glands concerned with milk secretion this is adesirable function in dairy cattle but undesirable in this invention forgrowing beef cattle in the production of high-quality beef. Further,this unique finding that the level of estrogen feeding is critical inlocalizing the estrogen primarily in the digestive tract is of evengreater significance since it assures against possible human hazardsfrom residual estrogen being present in the meat of treated beef cattleand sheep.

As is well known in the art, estrogenic substances vary in activity. Forexample, the dimethyl ether of diethylstilbestrol has been reported tobe four times as active as diethylstilbestrol itself. However, theranges set out above can be used for estrogenic substances other thanstilbestrol by administering an amount of the other estrogenic substancehaving an activity equal to the amount of stilbestrol specified. Withmany estrogens a comparison of activity can be made to determine thegeneral equivalence of estrogenic preparations as used in this inventionby determining the relative potency of the estrogenic substances instimulating uterine weight increases in immature female mice. This testprocedure is described in greater detail in Detection of estrogenicsubstances in alfalfa and clover hays fed to fattening lambs," by Chenget aL, Journal of Animal Science, January 1953. For certain estrogenssuch as those which tend to be stored in animal tissues, the cited testprocedure is not necessarily valid. For such estrogens potencydifferences are readily apparent, however, under actual conditions ofuse in growing beef cattle and sheep.

By way of illustration of the method, a beef cattle or sheep feedsupplement might be employed as the vehicle, composed principally ofsoybean meal and/or cottonseed meal and alfalfa meal, molasses, mineralsand vitamins. Such supplements are referred to in the trade as proteinsupplements. The estrogenic substance, such as stilbestrol, can readilybe incorporated in feed supplements of this type by first dissolving theestrogenic substances in a vegetable oil like cottonseed oil or soybeanoil. For example, 10 grams of stilbestrol might be dissolved in 227grams of oil. This oil solution would then be premixed with a measuredamount of the feed supplement, and thereafter the premixed materialwould be mixed with the whole body of a measured amount of the feedsupplement. For example, the above oil solution might be premixed with9% pounds of the supplement, and thereafter with enough of thesupplement to produce a 2,000 pound batch. Such estrogen-containingsupplements can be fed in various ways. However, they are preferablyused as a top dressing for the usual feed rations, or mixed therewith.

Other methods of incorporating the estrogenic substance in the feedmaterial can also be employed. Various dry mixing procedures may bedesirable for producing a dry product. By way of specific example, drydiethylstilbestrol can be mixed with a dry carrier such as powderedcalcium carbonate in the approximate concentration of one partdiethylstilbestrol to two parts calcium carbonate to form a premix. Thispremix can then be mixed with a feed material like soybean oil meal insuch manner that the final desired concentration is obtained.

The method of incorporating an estrogenic substance in beef cattle andsheep feed material first described above has particular advantages inpracticing the present invention, since it is of importance that theestrogenic substance be evenly and completely distributed throughout thefeed material, and this is difficult to accomplish because of theextremely small amounts of the estrogenic substance employed per poundof feed material and because of the insolubility of estrogenicsubstances in water. The preferred method admirably achieves the desiredresult. The estrogenic substance is soluble in the animal or vegetabletriglyceride oil, and the oil solution of the estrogenic substance isabsorbed by the finely-divided vegetable material. Good results areobtained by employing vegetable meals alone as the absorbent material,such as soybean meal, cottonseed meal, linseed meal, wheat bran, etc.Preferably, the vegetable meal employed is substantially free from oil,such as solvent-extracted soybean meal. The meal is then highlyabsorbent for the oil containing the estrogenic substance.

By the step described, a premix for incorporating an es trogenicsubstance in beef cattle feed material can be prepared. This premixcomprises a body of finely-divided absorbent vegetable materialsubstantially saturated with a triglyceride oil solution of anestrogenic substance. Preferably, substantially all of the oil isabsorbed by the vegetable material so that there is little free oil inthe body of material. This premix can then be combined with a beefcattle or sheep feed material to produce a feed material for use inpracticing the present invention.

While the method of this invention is applicable generally to thefattening of growing beef cattle and sheep, particularly good resultsare achieved in fattening steers. This is fortunate indeed, since steersare the principal beef-producing animals in the United States.

The following examples illustrate the method and feed material of thisinvention in greater detail.

EXAMPLE I Results with growing beef cattle indicate that estrogenicmaterials when orally administered such as in a beef cattle supplementalfeed, stimulates gains in live-weight and improved efficiency in feedutilization. The present example is presented as a general directionalexample or guide in practicing this invention in beef cattle feeding.The estrogenic material such as stilbestrol can easily be incorporatedin a cattle supplement at the time of manufacture. The amount whichshould be added to the cattle supplement should be approximately 10times the amount desired in the total cattle ration since most cattlesupplements in practice are fed at the rate of 10% of the total amountof feed which cattle normally consume. For example, if one wished tofeed 0.03 milligram of stilbestrol per pound of total feed consumed bycattle, then 0.3 milligram should be placed in each pound of the cattlesupplement. Likewise, if one wishes to feed 1.0 milligram of stilbestrolper pound of total ration consumed, then 10.0 milligrams of stilbestrolshould be placed in each pound of the cattle supplement. The placing ofthese small quantities of materials in cattle supplements is most easilyaccomplished by first diluting them in a suitable solvent, for example10 gms. of stilbestrol dissolved in 227 gms. of peanut oil. This amountof oil solution is sufficient for mixing with l ton. of cattlesupplement if one wishes to supply milligrams of stilbestrol per poundof supplement. To facilitate the most uniform mixture, it is best topremix the oil solution with a small quantity, such as 9 /2 lbs, of oneof the cattle supplement ingredients.

EXAMPLE ll Diethylstilbestrol in trace amounts was placed in the feed offattening steers in three feeding experiments. In the first experiment,3 lots of yearling steers were fed similar fattening rations containingseveral levels of diethylstilbestrol. During a 43-day feeding periodthese additions supplied 5 mgs., mgs., and no diethylstilbestrol persteer daily in each of the respective lots. in the second experiment, 4lots of 8 steers individually weighing about 700 pounds, were fed thefollowing ration for I12 days: corn ad libitum, 12 pounds of silage, 2pounds of hay, and 2 pounds of soybean oil meal per animal per day.Diethylstilbestrol was added to the soybean oil meal to provide eachsteer in the respective lots the following levels: none, 2.5 mgs., 5mgs., and 10 mgs. Two lots of 8 steers each averaging initially 77 5lbs. were fullfed for 111 days a mixture of approximately 65% groundshelled corn and 35% ground corncobs in the third and final experiment.Lot 1 in this experiment received a simple protein supplement (3 lbs.daily per steer) consisting of soybean oil meal with nodiethylstilbestrol added. Lot 2 received a complex supplement in anamount equal to that fed to lot 1, but containing sufiicientdiethylstilbestrol to supply 5 mgs. per steer daily.

The feedlot behavior of the cattle receiving diethylstilbestrol wasnormal in every respect. This was true in each of the 3 experiments evenwhen particular attention was focused upon characteristics which mightconceivably develop from stilbestrol feeding such as restlessness,riding, high tailheads, lactation and udder development.

The more pertinent results of these experiments are presented in TableI.

Table I EFFECTS OF DlE'll-IYLSTILBES'IROL- IN THE RATIONS OF FATTENINGSTEEHS Mgs. Diethylstilbestrol per steer daily Experiment I (43 days):

Av. Dally Gain lbs 2.13 1K3 2.50 Feed Requlr ler lbs. galn,

lbs L144 929 1,065 Experiment II 112 days):

Av.Dally aln,lb:L. v 2.23 2.46 2.04 3.06 Feed Required For 100 lbs.gain,

5 A 940 R64 874 756 Experiment III (112 days);

Av.Dally (lalu,lhs...,. 2.33 2,91 Feed Requlred Per llXJ lbs. (lain,

lbs 978 919 Within each experiment these data show that incorporation oftrace amounts of diethylstilbestrol in the rations of fattening steersmarkedly increased weight gains when compared with the performance ofthe animals not receiving diethylstilbestrol. In every case steersreceiving diethylstilbestrol required less feed per unit of gain thancomparable steers not fed this material. The financial returns from thecattle when sold showed consistently greater profits in the 3experiments in lots receiving diethylstilbestrol as compared to lots notreceiving diethylstilbestrol. This greater profit amounted to as much as$26.00 per steer in one of the experiments.

The cattle in the 3 experiments produced carcasses which graded U. S.choice to low-prime. The carcasses produced by the most rapidly gaininganimals (fed diethylstilbestrol) possessed quality characteristicssimilar to or slightly superior to those found in carcasses from thecontrol lot as determined by grade characteristics and the yield of leanand fat from the 9-10-1- rib sections. No residues of stilbestrolremained in the fat and muscle tissues when analyzed using bio-assaymethods sufliciently critical to measure approximately one hundredth ofone part per million of the hormone had it been present in the tissues.

Summarizing, the placing of trace amounts of diethylstilbestrol in thefeed of fattening beef cattle increased liveweight gains as much as 35%over control animals not receiving diethylstilbestrol and reduced feedcosts per unit of gain as much as 20%. Profits from beef cattle feedingwere approximately doubled by using diethylstilbestrol. No reduction inthe fatness of the cattle or the quality of meat produced was noted whenthe diethylstilbestrol was incorporated in the cattle feeds. Also nostilbestrol residues remained in the beef tissues following slaughter.

EXAMPLE lll Two additional cattle experiments were carried out todetermine the influence of oral administration of diethylstilbestrol ingrowing beef cattle being fed high- 7 roughage rations. The previous 3cattle experiments described in Example II made use of high-graingrowing rations. It was therefore desirable to establish whetherdiethylstilbestrol would exert favorable influences in high roughagerations similar to the favorable results obtained on the high-grainrations fed to growing beef cattle.

The first high-roughage ration tested consisted of cornstalk silagefullfed with the following feeds in the rations being limited per animaldaily to 5 lbs. of bromealfalfa hay, 2 lbs. of ground car com, and 2lbs. of protein supplemental feed. Ten yearling steers weighing 625 lbs.at the start of the experiment were fed this ration for 127 days andtheir rate and cost of gain determined for the entire feeding period.Ten similar steers were fed during the same period a similar ration towhich 5 milligrams of diethylstilbestrol was incorporated in the 2 lbs.of protein supplemental feed being fed daily. The results of thisexperiment showed a favorableness to stilbestrol when added to thehigh-roughage ration similar to the good results earlier obtained whenfeeding highgrain rations. The cattle without stilbestrol gained 1.11lbs. daily per head whereas the cattle receiving stilbestrol gained 1.22lbs. daily. The feed costs of liveweight gains were reduced from 23.0per lb. to l9.2 per pound with this small feed addition ofdiethylstilbestrol to the ration. No undesirable side effects such asriding, mammary development, and lactation were observed in the steercattle at any time during this experiment.

The second high-roughage ration to which diethylstilbestrol was addedconsisted of approximately similar feeds to those just described exceptthe corn grain and protein supplement fed was essentially doubled inamount such that the cattle received approximately 8 lbs. of concentratefeeds daily per animal in addition to all the roughage they wouldconsume. Eight 625-lb. steers received this high-roughage ration for 140days without diethylstilbestrol and 8 similar steers during the sameperiod received a similar ration to which 5.5 milligrams ofdiethylstilbestrol was incorporated in the daily protein supplementallowance furnished each animal. Again a favorable response was obtainedfrom the oral administration of stilbestrol in the high-roughage rationconsumed by these growing beef cattle. Liveweight daily gains per animalwere stimulated from 1.72 lbs. to 2.00 lbs. by the stilbestrol additionin the feed. Costs of gains were reduced by 18%. No undesirable efiectsattributable to diethylstilbestrol feeding were noted in the cattle atany time.

EXAMPLE IV It appeared desirable to test the value of oral administration of diethylstilbestrol in different types of beef cattle andsee if similar good results could be obtained as noted when stilbestrolwas included in different types of cattle rations. Accordingly twofurther beef cattle experiments were conducted with feedingdiethylstilbestrol. One experiment made use of heavy weight steersweighing between 1000 and 1300 lbs. per animal. In the second experimentbeef heifers were used weighing initially 640 lbs. on the average. Inall previous experiments described in Examples 11 and ill, steers wereused weighing from 625 lbs. to 775 lbs. initially per animal.

Two lots of animals each of heavy weight steers were fullfed a high cornration, limited hay, and protein supplemental feed over an 84-dayperiod. One lot received no stilbestrol while the other lot receivedstilbestrol in the protein supplemental feed at a level such that eachsteer received 9 milligrams of hormone daily. Liveweight daily gain peranimal was stimulated from 2.32 lbs. to 2.95 lbs. by the stilbestrolfeed addition. Feed cost per lb. of liveweight gain was reduced from22.34! down to 17.51:, thus indicating the profitableness of addingdiethylstilbestrol to heavy weight growing beef cattle. The cattle inthe feedlot showed no untoward eflects from diethylstilbestrol feeding.They sold well on the market and their carcasses proved to be slightlysuperior to carcasses from animals not receiving diethylstilbestrol intheir feed. No detectable stilbestrol residue remained in the meat whenanalyzed critically in the laboratory. The only place wherediethylstilbestrol residues were present were within the contents of thedigestive tract and in the bile emptying into the digestive tract. Thisfinding is in direct contrast to the results reported by others withsubcutaneous injection of stilbestrol pellets which leaves behindstilbestrol residues throughout the meat tissues of cattle.

In the last cattle experiment, growing beef heifers were tested withrespect to their responsiveness to feeding diethylstilbestrol. One lotof 8 heifers weighing initially 640 lbs. was fed for 112 days a highgrain growing ration to which no diethylstilbestrol was added. Twoadditional lots of 8 heifers each were fed during the same 112 dayssimilar rations except for stilbestrol additions to the feed. Thestilbestrol additions in the two lots were at the respective rates of 6and 12 milligrams per heifer daily. Liveweight gains were stimulated inthe heifers similar to the stimulation noted with steers. Thisstimulation amounted to about 20% or an additional third of a lb. gaineach day a heifer was fed stilbestrol. Feed costs of gains were reducedand the profitableness of cattle feeding thereby increasedsubstantially.

No undesirable side effects such as udder development occurred in theheifers at any time. The beef carcasses produced were of excellentquality. Also no stilbestrol residues were found in the meat tissues.The only residues being present were confined to the contents of thedigestive tract and to the bile of the liver.

During the winter months of 1951-52 two lots of 20 western feeder lambseach were fed for 78 days a fattening ration composed of 56 partsshelled com, 40 parts mixed clover hay and 4 parts soybean oil meal.This ration was characterized further as containing the estrogeniematerial (genistein) equivalent to l microgram of stilbestrol per poundof ration. The lambs made exceedingly good gains in body weight (average.45 lb. per lamb daily) as compared to lamb gains of approximately .33lb. when fed this same type of ration without estrogenic activity. Twoadditional lots of lambs were injected with stilbestrol pellets (two 15mg. pellets per lamb) in addition to the above ration containinggenistein in an etfort to determine whether the genistein was l00%elfective in stimulating maximum weight gains in lambs. These lambsreceiving stilbestrol injected failed to gain faster than the lambswithout stilbestrol pellets, indicating that the genistein orallyadministered in the feed was effective.

EXAMPLE V A second lamp experiment was carried out during the summermonths of 1952 which was essentially a duplication of the aboveexperiment. Again genistein orally administered in the hay consumed bylambs proved just as effective in stimulating gains in fattening lambsas did further administration of stilbestrol pellets.

EXAMPLE VI During the fall of 1952 the oral administration of genisteinwas further tested with respect to its ability to stimulate growth inlambs and its ability to bring about im provement in the lamb meat beingproduced. Since much difiiculty and expense were involved in securing asupply of genistein, which had to be extracted from a special supply ofhay with pure ethylalcohol, only a limited number of lambs (8) were usedin this experiment. Great care was taken in obtaining lambs ofuniformity with respect to breeding, size, fleshiness and previousfeeding history. The 8 lambs selected were placed in individual feedingpens and allowed free access to all the feed and water they wouldconsume throughout a 63-day feeding period. Four of the lambsreceivedthe following basal feed mixture: Coarsely ground hay 50.00%,cracked corn 32.63%, cane molasses 15.00%, protein and mineralsupplement 2.37%. The other four lambs received a similar feed mixtureto which 8 grams of genistein was added per 100 lbs. of feed mixture.The genistein was incorporated in the mixture by first mixing it withthe molasses and then mixing the molasses with other ingredients. Thisration thus compounded contained 2 stilbestrol units per pound.

The four lambs receiving the basal mixture each made an average dailyliveweight gain of .33 of a pound during the 63-day feeding period. Thelambs receiving the genistein gained 12% faster or .37 of a pound dailyduring the same period.

Each of the 8 lambs fed were slaughtered immediately at the close of thefeeding experiment. Dressing percentage averaged slightly higher in thegenistein-fed group than in the control group, indicating more ediblemeat was produced with the use of genistein.

The edible meat was studied in detail by taking a 3-rib cut from eachlamb carcass. Separation of this 3-rib cut into 3 fractions namely fat,lean, and bone, indicated that somewhat more lean meat was produced fromthe genistein-fed animals and substantially more fattening occurredwhere this estrogenic substance was fed. The average fat percentage ofthe 3-rib cut from the basal group of carcasses was 34.5 whereas thecomparable figure for the genistein carcasses was 43.9%.

The results of this experiment can be summarized by saying theestrogenic substance genistein caused lambs to gain faster, to producemore edible and salable meat, and meat of higher quality as judged bydegree of fatness.

EXAMPLE VII In a companion experiment to the experiment presented inExample VI, 8 lambs were selected and fed in the same manner asdescribed above except stilbestrol (1.5 micrograms per lb.) was used inthe second ration instead of genistein. The stilbestrol was incorporatedin the ration by first dissolving the pure chemical in peanut oil suchthat 1 gm. of oil contained 0.01 mg. of stilbestrol. The oil solutionwas then mixed in the total ration to supply the desired amount ofstilbestrol.

At the end of a 70-day feeding period the lambs receiving stilbestrolgained 40% faster than the lambs receivno stilbestrol. The average dailygains of the 2 groups were .48 and .34 lbs. respectively. Uponslaughtering the lambs immediately at the close of the experimentdressing percentage was higher in the stilbestrol-fed lambs (52.8%) ascompared with (50.9%) for the basal lambs receiving no stilbestrol.

In summary, the results of this experiment demonstrated that stilbestrolwhen orally administered not only stimulated gain in liveweightmarkedly, but resulted in higher dressing percentage indicating moresalable meat produced and meat of higher quality.

EXAMPLE VIII During the spring of 1953 twenty-eight lambs were employedin testing the most efiective levels of orally administering stilbestrolin lamb feeds. Four lambs were fed a basal ration mixture composed of 50parts ground clover hay, 38 parts ground com, 10 parts molasses and 2parts minerals with urea. This basal mixture contained no stilbestrol. Asecond group of 4 lambs received the basal mixture to which was added1.5 micrograms of stilbestrol per lb. of mixture. The third groupreceived 3.0 micrograms of stilbestrol per lb. of ration, the fourthgroup received 6.0 micrograms, and the fifth group of 4 lambs received12.0 micrograms of stilbestrol per pound of the basal mixture.

The sixth group of 4 lambs received stilbestrol by another method ofadministration, namely, by implantation of a mg. stilbestrol pelletunder the skin of each lamb at the beginning of the feeding period. Thepurpose of 10 this group was to compare the implantation method ofstilbestrol administration with the method of oral administration.

The seventh and final lot of 4 lambs received the basal feed mixture towhich 0.2 gm. of genistin was added per pound of final mixture. Thisgenistin amounted to 4 units of stilbestrol per pound of ration. Thegenistin used was extracted from soybean oil meal and purified to a highdegree of purity.

The gains made by all the lambs on the various treatments wereconsidered good for the 42-day feeding trial. The lambs receiving thelower levels of stilbestrol in their respective ration, however, gainedsignificantly more than the lambs receiving no stilbestrol. The averagedaily gains were as follows:

Pounds Lot l-Basal-no stilbestrol .46 Lot 2-1.5 meg. stilbestrol per lb.ration .58 Lot 3-3.0 meg. stilbestrol per lb. ration .53 Lot 46.0 meg.stilbestrol per lb. ration .49 Lot 5l2.0 mcg. stilbestrol per lb. ration.40 Lot 6Stilbestrol pellet .40 Lot 7Genistin (4 stilbestrol) .53

As in the case of Example VII, the best gaining stilbestrol-fed lotgained approximately 40% faster than the group of lambs on the basalration containing no stilbestrol. The lambs receiving the stilbestrolpellet failed to gain as much as the control lambs. These pelleted lambsshowed undesirable side etfects, namely, increased sexualcharacteristics. The lambs receiving genistin in their feed gainedsignificantly more than the control lambs and approximately the sameamount as lambs getting an equivalent amount of estrogenic substances inthe form of stilbestrol.

Removal of the 3-rib sections from each of the lambs after slaughterrevealed that the lambs receiving either form of estrogen (stilbestrolor genistin) had superior meat carcasses carrying a better degree offatness when compared to the control lambs receiving no estrogeniematerial in their feeds.

While of course there is some variation from animal to animal in regardto the response obtained by treating the animal in accordance with themethod of this invention, it can be stated generally that increases withbeef cattle and sheep in the rate of weight gain of the order of 10 to30% are usual. It has been found, as indicated above, that not only doesthe method of this invention increase the rate of weight gain of theanimal but also that the meat produced is of as good or better quality.One indication of this is that the meat tends to contain more fat andthat the fat is better distributed. Further, animals fattened inaccordance with this invention provide a greater dressed weight ofsalable meat for the same feeding period. Summarizing, the method ofthis invention provides a means for producing more beef and sheep meatin the same time with a reduced amount of feed without impairing thequality of meat.

While in the foregoing specification this invention has been describedin considerable detail and specific em bodiments thereof have been setforth, it will be apparent to those skilled in the art that thisinvention is subject to other embodiments and that many of the specificdetails set forth can be varied considerably without departing from thebasic concepts of the invention.

I claim:

1. The method of growing and fattening meat-producing animals s'electedfrom the class consisting of immature beef steers, immaturenon-lactating beef heifers, and immature sheep, comprising orallyadministering an estrogenic substance to said animals at spacedintervals of time, and regulating the quantities of said estrogenicsubstance administered to said animals to accelerate the rates of weightgain of said animals but without appreciably afiecting theirreproductive systems, whenever the animals selected from said group areheifers said heifers remaining free from milk secretions throughout thecourse of said administration, the amount of said estrogenic substanceadministered to said animals when said animals are said steers and whensaid animals are said heifers having an activity ranging from about 0.1to 8 milligrams of diethylstilbestrol per 100 pounds of body weight per24 hours, the amount of said estrogenic substance administered to saidanimals when said animals are said sheep having an activity ranging fromabout 0.01 to 5.0 milligrams of diethylstilbestrol per 100 pounds ofbody weight per 24 hours, whereby more beef and sheep meat can beproduced in the same time with a reduced amount of feed withoutimpairing the quality of the meat.

2. The method of claim 1 in which said estrogenic substance isdiethylstilbestrol.

3. The method of claim 1 in which said estrogenic substance is asynthetic estrogen having a molecular structure including twohydroxyphenyl groups.

4. The methd of claim 1 in which said animals are immature steers.

5. The method of growing and fattening meat-producing animals to producemore meat in the same time with a reduced amount of feed withoutimpairing the quality of the meat, said animals being selected from theclass consisting of immature steers, immature non-lactating beefheifers, and immature sheep, comprising orally administering anestrogenic substance to said animals at spaced intervals of time oversubstantial portions of their growth periods, regulating the quantitiesof said estrogenic substance administered to said animals to acceleratethe rates of weight gain of said animals but without appreciablyaffecting their reproductive systems, the amount of said estrogenicsubstance administered to said animals when said animals are said steersand when said animals are said heifers having an activity ranging fromabout 0.1 to 8 milligrams of diethylstilbestrol per 100 pounds of bodyweight per 24 hours, the amount of said estrogenic substanceadministered to said animals when said animals are said sheep having anactivity ranging from about 0.01 to 5.0 milligrams of diethylstilbestrolper 100 pounds of body weight per 24 hours, and thereafter slaughteringsaid animals to obtain their meat-providing carcasses.

6. The method of growing and fattening immature beef cattle, comprisingorally administering a synthetic estrogenic substance-to said beefcattle at spaced intervals of time over substantial portions of theirgrowth periods, regulating the quantities of said estrogenic substanceadministered to said beef cattle to accelerate the rates of weight gainof said beef cattle but without appreciably affecting their reproductivesystems, the amount of said estrogenic substance administered over each24 hour period per 100 pounds of body weight having an activity rangingfrom about 0.1 to 8 milligrams of diethylstilbestrol, and thereafterslaughtering said beef cattle to obtain their meat-providing carcasses,whereby more feed meat can be produced in the same time with a reducedamount of feed without impairing the quality of the meat.

7. A method of growing and fattening immature sheep, comprising orallyadministering a synthetic estrogenic substance to said sheep at spacedintervals of time over substantial portions of their growth periods,regulating the quantities of said estrogenic substance administered tosaid sheep to accelerate the rates of weight gain of said sheep butwithout appreciably aflecting their reproductive systems, the amount ofsaid estrogenic substance administered over each 24 hour period perpounds of body weight having an activity ranging from about 0.01 to 5.0milligrams of diethylstilbestrol, and thereafter slaughtering said sheepto obtain their meatproviding carcasses, whereby more sheep meat can beproduced in the same time with a reduced amount of feed withoutimpairing the quality of the meat.

8. The method of growing and fattening meat-producing animals selectedfrom the class consisting of immature beef steers, immaturenon-lactating beef heifers, and immature sheep, comprising mixing aquantity of a synthetic estrogenic substance with a feed material forsaid animals, feeding portions of the resulting mixture to said animalsat spaced intervals of time over substantial portions of their growthperiods, regulating the amounts of said mixture fed to said animals toaccelerate the rates of weight gain of said animals but withoutappreciably atfecting their reproductive systems, whenever the animalsselected from said group are heifers said heifers remaining free frommilk secretions throughout the course of said feeding, the amount ofsaid estrogenic substance fed to said animals having an activity rangingfrom about 0.1 to 3 milligrams of diethylstilbestrol per 100 pounds ofbody weight per 24 hours, and thereafter slaughtering said animals toobtain their meatproviding carcasses.

9. The method of claim 8 in which said estrogenic substance isdiethylstilbestrol.

10. The method of using diethylstilbestrol for the treatment of beefcattle to produce more beef meat in the same time with a reduced amountof feed without impairing the quality of the meat, comprising dissolvinga measured quantity of diethylstilbestrol in a tri glyceride oil toobtain said measured quantity in a dellnite volume of solution, mixingsaid definite volume of solution with a predetermined amount of anedible vegetable material, said vegetable material being in afinelydivided absorbent condition and said predetermined amount beingsufiicient to absorb said solution, eontinuing said mixing until saidsolution has been uniformly distributed throughout and absorbed by saidvegetable material, thereby obtaining a premix of knowndiethylstilbestrol content which is especially adapted for oraladministration to beef cattle, mixing said premix with a largerestablished quantity of a beef cattle protein feed supplement, andfeeding said supplement to beef cattle in such amounts that said beefcattle receive about 0.1 to 3 milligrams of diethylstilbestrol per 100pounds of body weight per 24 hours.

References Cited in the file of this patent UNITED STATES PATENTS Turneret al Feb. 13, 1951 Turner Mar. 18, 1952 OTHER REFERENCES 4, pages24-36.

46, Indiana Agrl.

Andrews et al.: Mimeo. No. A. H. Exp. Sta., April 21, 1950, two P 8UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.2,751,303 June 19, 1956 Wise Burroughs It is hereby certified that errorsppears in the printed specification of the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 6, line 55, for "9-lO-l-" read 9-10-11 column 11, line 58, for"feed" read beef Signed and sealed this 14th day of August 1956.

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Officer Conmissioner ofPatents

1. THE METHOD OF GROWING AND FATTENING MEAT-PRODUCING ANIMALS SELECTEDFROM THE CLASS CONSISTING OF IMMATURE BEEF STEERS, IMMATURENON-LACTATING BEEF HEIFERS, AND IMMATURE SHEEP, COMPRISING ORALLYADMINISTERING AN ESTROGENIC SUBSTANCE TO SAID ANIMALS AT SPACEDINTERVALS OF TIME, AND REGULATING THE QUANTITIES OF SAID ESTROGENICSUBSTANCE ADMINISTERED TO SAID ANIMALS TO ACCELERATE THE RATES OF WEIGHTGAIN OF SAID ANIMALS BUT WITHOUT APPRECIABLY AFFECTING THEIRREPRODUCTIVE SYSTEMS, WHENEVER THE ANIMALS SELECTED FROM SAID GROUP AREHEIFERS SAID HEIFERS REMAINING FREE FROM MILK SECRETIONS THROUGHOUT THECOURSE OF SAID ADMINISTRATION, THE AMOUNT OF SAID ESTROGENIC SUBSTANCEADMINISTERED TO SAID ANIMALS WHEN SAID ANIMALS ARE SAID STEERS AND WHENSAID ANIMALS ARE SAID HEIFERS HAVING AN ACTIVITY RANGING FROM ABOUT 0.1TO 8 MILLIGRAMS OF DIETHYLSTILBESTROL PER 100 POUNDS OF BODY WEIGHT PER24 HOURS, THE AMOUNT OF SAID ESTROGENIC SUBSTANCE ADMINISTERED TO SAIDANIMALS WHEN SAID ANIMALS ARE SAID SHEEP HAVING AN ACTIVITY RANGING FROMABOUT 0.01 TO 5.0 MILLIGRAMS OF DIETHYLSTILBESTROL PER 100 POUNDS OFBODY WEIGHT PER 24 HOURS, WHEREBY MORE BEEF AND SHEEP MEET CAN BEPRODUCED IN THE SAME TIME WITH A REDUCED AMOUNT OF FEED WITHOUTIMPAIRING THE QUALITY OF THE MEAT.